You don't need to add additional markup to source code and neither to specify the language of source code snippets since prettify will guess. Code prettify module for Drupal is compatible with WYSIWYG editors and includes several themes to customize the colors and styles of source code snippets.

Google Code Prettify JavaScript library supports all C-like (Java, PHP, C#, etc), Bash-like, and XML-like languages without need to specify the language and has customizable styles via CSS. Widely used with good cross-browser support. For more information, visit their project page on code.google.com.